Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance, beginning period	$ 0	$ 2.5	$ 2.5
Additions for tax positions of prior years	0		0
Additions for tax positions of current year	0		0
Reductions for tax positions of prior years	0	(2.5)	0
Reductions for lapse of statute of limitations	0		0
Balance, ending period	$ 0	$ 0	$ 2.5